FAKHR-AD-DIN AR-RAZI, fäk'r-ȧd-dḗn' är-rä'zḗ, also known as Ibn al Khatin (1149-1210). A Mohammedan philosopher and theologian. He was born at Rai, Tabarestan; first studied with his father, and later at Merv and Maragha, where he was one of the pupils of Al Majd al Jili, who in turn had been a disciple of Al-Ghazali. He was accused of rationalism, despite the fact that he restored many to the orthodox faith. Nevertheless, his commentary on the Koran, entitled Māfatih-al-haib (best ed., 6 vols., in the year 1278 of the Hejira), is the most varied and many-sided of all extant works of the kind, comprising most of the material of importance that had previously appeared. Fakhr-ad-din also devoted himself to a wide range of studies, and is said to have expended a large fortune on experiments in alchemy. He taught at Rai and Ghazni, and became head of the university founded by Mohammed Ibn Tukush at Herat.